Many neurological disorders involve the loss of spatial abilities. Such disorders will often involve deficits in motor control (e.g., reaching to a target, or posting a letter). It is important to understand how sensory information is utilized for these motor control tasks. W therefore propose to explore how the central nervous system compensates for self generate Coriolis forces during active trunk rotation under altered sensory-motor adaptation as a way to investigate adaptive force control and self- calibration of reaching movement. In addition, we will investigate the use of non-mechanistically supportive touch in stabilizing posture and balance, which is often a primary replacement for visual and vestibular information in patients with vision loss or a non-functional labyrinth. The first experiment will investigate how low systematic displacement of a platform, upon which the subject stands, affects subsequent reaching movements. During adaptation, the platform will systematically rotate (incrementally, to avoid gross disruption of balance and posture) to either reduce the amount of inertial torso rotation by +, or to double the mount of inertial rotation. Subsequent reaching motions (with and without body rotation) will be used to assess the compensation for Coriolis forces by the altered inertial torso rotation/platform relationship. Another experiment will investigate the role of systematic displacement of non- supportive guide provided to the hand during (subsequent) simultaneous turning and reaching movements. During adaptation, the non-supportive platform will be touched lightly by the hand of the observer while turning the trunk left and right. The hand platform will systematically rotate to either attenuate or amplify the amount of relative hand/body rotation. Subsequent reaching motions (with and without body rotation) will be used to assess the compensation for Coriolis forces by the altered inertial hand displacement/platform relationship.